Did these companies allocate their new capital in the most effecient manner (like by bolstering reserve funds to weather a black swan)?

At tax time, just allocate your expenses between person and the rental. 

You should allocate part of the purchase cost to land, and I just randomly took 20% to land.

Allocation of rent.

You cannot "steal" from one element's allocated reserve to pay for something else deemed more important at the time, because the element you steal from still has it's own timeline to follow.Regarding your railings, I doubt this was a real surprise, particularly if Insurance was requiring it as well.

Hello,You should have the security deposit allocated to a specific business account. 

You will need to expect and allocate time to additional paperwork but establishing a strong working relationship with the housing adviser in your area will really help.

I allocated first to equities, and put large lump sums throughout the years.

An LLC makes some expenses easier to allocate to a business, it has it's own accounting, so buying office supplies is generally accepted by the IRS as opposed to you buying paper for your printer at home.

Thanks all for the input - I've never set one up before but I imagine you can create properties and track from that perspective plus the overall rental business (ex. some expenses get allocated amongst multiple properties)?